Some prior patents or publications which may be of interest are listed below:
Patent No. Inventor(s) Issue Date 2,782,056 Allegretti 02/19/57 1,029,687 (GB) Print & Plastics 05/18/66 3,292,951 Schoenberger 12/20/66 1,289,821 (GR) Neuse 02/27/69 2,091,234 (FR) IPC Services 01/14/72 3,739,412 Card et al 06/19/73 3,840,254 Shatzkin 10/08/74 3,957,287 Hall et al 05/18/76 4,009,498 Staats 03/01/77 2,145,033 A (GB) Smith 03/85 4,531,874 Voges 07/30/85 240-176-A (DD) Inst Grafische Tech 10/22/86 2,197,156 (UK) Peleman 05/88 4,828,645 Van Bortel 05/09/89 4,958,974 Schenk 09/25/90 412,742 A2 (EPC) Schenk 02/13/91 5,078,563 Lolli 01/07/92 5,246,325 Morishige et al 09/21/93 5,340,155 Podosek 08/23/94 9,201,094 (BG) Peleman 12/14/92 (filed) 9,300,981 (BG) Peleman 09/21/93 (filed) 5,425,554 Lamanna 06/25/95 5,733,087 Gwyn 03/31/98
It is a common desire in, for example, office settings, to bind sheet materials together, such as, for example, a selected collection of papers, along one edge for finished reports, product information, data collection, etc., and the like. To achieve this, a binding industry has been created to produce various approaches to binding the selected materials together using, for example, spiral binding, adhesive binders, pin binders, etc.
In a simple method of adhesive binding, the binding assembly includes a binding element, typically a file consisting of a front cover, a back cover and a spine channel on the inside of which is provided an amount of glue which melts upon the influence of heat. The sheet materials (or sheets) are joined together as a unit and placed inside the binding element in contact with the glue. Upon application of heat, the glue melts and the edges of the sheets intrude into the glue layer. After the heat is removed from the binding element, the glue solidifies which results in the sheets being bonded to each other and retained in the binding cover or element by means of the glue. See, for example, U.S. Pat. No. 5,078,563 (Lolli), U.S. Pat. No. 5,425,554 (Lamanna), and G.B. 2,145,033 (Smith).
Typically, the spine channel has a "U" shape cross-section. A heat-flowable, relatively thick, adhesive strip layer is located inside the "U" shape and along its bottom. Additionally, in the prior art, back and front covers (transparent or opaque) may be attached along each of the spine side walls or edges.
It is also known in the prior art to apply an element of a heat conducting material, such as metal, on the spine. The heat conducting element allows an efficient transfer of heat to the glue, such that the glue melts uniformly across the inside of the spine. The heat conducting element may have a "U-shaped" profile which also functions to reinforce and support the connection between the glue and the edges of the sheets. When the bundle of sheets are laid down and opened, or when the pages are turned, the parallel walls of the U-shaped element supports the weight of the paper and guards the glued connections. See, for example, Lamanna '554, and G.B. 2,197,156 (referenced in Lamanna '554).
Typically, the U-shaped heat-conducting element is located at the inside of the file. In such an arrangement, it is difficult to place uniformly all the sheets into the U-shaped profile, especially when dealing with thick bundles. The most recent, asserted improvement to the prior art, as disclosed in U.S. Pat. No. 5,425,554, issued to Lamanna, attempts to address that problem by positioning the actual file on the inside of the heat conducting element. A further disclosure has the file covers only partially adjacent the "U-shaped" heat conducting element; the typical spine is replaced with the heat-conducting element, then acting as the spine of the binding element. The glue is applied directly to the inside of the spine/heat-conducting element.
In this prior art, the spine is specifically manufactured from a hard, heat-conducting material with little or no bendability, typically, a metal, such as steel. For primarily aesthetic purposes, a covering is applied on the exposed exterior of the spine or completely around the spine. The cover is usually an "elegant," decorative material such as printed paper.
The above-mentioned metal spine design may be incorporated with another recent improvement in binding assemblies, the cover-less spine. In this disclosure, the front and back covers of the file are excluded. In previous disclosures by the present inventor (see the Gwyn applications referred to above), the cover-less spine is equipped with temporary, easily removable, guide members for guiding the sheets into the spine.
The above-mentioned metal spine design has also been incorporated into "hard-bound" book-like covers.
Although recent improvements in the prior art have resulted in a simpler, less expensive method of binding sheet materials, there is still room for further improvements. Problems persist in the prior art which have not been successfully addressed. Meanwhile, new challenges have surfaced from recent improvements.
The primary problem with the use of a metal element for the spine or heat-conducting element, arises when the spine is subject to certain bending loads and other external loads and strain present during shipping, handling and use. The stiff, inflexible metal element, and thus the spine, has a tendency to become and stay crimped, thereby mis-aligning the sheet materials, and further inducing excessive wear. It also difficult for a book or bound collection of sheet materials to remain open at certain pages when laid down. This is not only unattractive and burdensome, but it also creates an unprofessional appearance to the bound report, product catalog, etc.
Another undesirable aspect of the metal spine is that it generally appears dull and uninviting. As an attempted remedy, a decorative covering around the binding element is usually added to hide the metal surface; see, e.g., the Lamanna ('554) patent. Although the present invention uses an aesthetically pleasing cover, this prior art approach, however, significantly compromises the simplicity in the manufacture and application of the binding assembly and adds far more complexity to the manufacturing process.
Another problem persistent in known adhesive binding assemblies is related to the use of overly large quantities of hot-melt glue for the heating and binding operation, with such large quantities being added apparently to ensure adhesion, with the glue typically being overly added in a long, continuous strip of a relatively great thickness. However, not to mention the cost of such an excessive amount of glue or adhesive, during the heating step, the adhesive glue has the tendency to flow up and around, not only the edges of the sheet materials to be bound, but beyond the binding areas and onto exposed areas of the sheet materials, covers or upper edges of the channel spine. In the invention a more appropriate amount of glue is added in a straight, continuous ribbon or, alternatively, in the form of spaced dots of glue, although this aspect is not central to the present invention's patentable contribution to the useful arts.
In the present invention preferably both covers are included, both of which typically are opaque, and which, unlike most of the prior art, provides a relatively "hard," thicker cover, producing a "hard-bound" book-like cover product without using any internal metal spine, which then can be used in a final, user-applied heating step to produce a final, "hard-bound" book-like product.
The "hard-bound" book-like product of the invention has been long sought after in the prior art but until the present invention has not been possible in an economical, "hard" but somewhat flexible product that avoids the problems of the hard covers of the prior art, particularly those that include an internal metal spine forming the cover's central channel.
The present invention thus is designed to provide an alternative solution which avoids, or at least diminishes, the prior art problems, while providing new, valuable and innovative improvements over the prior art.